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991.
Genetic variants in LEP,LEPR, and MC4R explain 30% of severe obesity in children from a consanguineous population 下载免费PDF全文
992.
Dopamine synthesis rate and cyclic AMP concentration were measured in synaptosomes prepared from rat striatum. Dopamine synthesis rate was decreased by the addition of either adenosine deaminase or 8-phenyltheophylline, an adenosine receptor blocker, and was increased by the addition of 2-chloroadenosine. The addition of L-glutamate in the absence of adenosine deaminase decreased both dopamine synthesis rate and cyclic AMP concentration; in the presence of adenosine deaminase, glutamate had no effect on basal dopamine synthesis, but enhanced K(+)-stimulated synthesis. Both these effects of glutamate were abolished in Ca2(+)-free medium or in the presence of 2-amino-5-phosphonovalerate, an N-methyl-D-aspartate (NMDA) receptor blocker. In Mg2(+)-free medium with adenosine deaminase, glutamate enhanced both basal and K(+)-stimulated synthesis. These results suggest that dopaminergic terminals have A2 adenosine receptors, whose activation can stimulate dopamine synthesis by a cyclic AMP-dependent mechanism, and NMDA receptors, which modulate dopamine synthesis by a Ca2(+)-dependent mechanism. 相似文献
993.
Rob W Briddon Basavaprabhu L Patil Basavaraj Bagewadi Muhammad Shah Nawaz-ul-Rehman Claude M Fauquet 《BMC evolutionary biology》2010,10(1):97
Background
Viruses of the genus Begomovirus (family Geminiviridae) have genomes consisting of either one or two genomic components. The component of bipartite begomoviruses known as DNA-A is homologous to the genomes of all geminiviruses and encodes proteins required for replication, control of gene expression, overcoming host defenses, encapsidation and insect transmission. The second component, referred to as DNA-B, encodes two proteins with functions in intra- and intercellular movement in host plants. The origin of the DNA-B component remains unclear. The study described here was initiated to investigate the relationship between the DNA-A and DNA-B components of bipartite begomoviruses with a view to unraveling their evolutionary histories and providing information on the possible origin of the DNA-B component. 相似文献994.
995.
The effect of NH
4
+
on the regulation of NO
3
–
and NO
2
–
transport systems in roots of intact barley (Hordeum vulgareL.) seedlings grown in NO
3
–
or NO
2
–
was studied. Ammonium partially inhibited induction of both transport systems. The inhibition was less severe in NO
2
–
-fed than in NO
3
–
-fed seedlings, presumably due to lower uptake of NH
4
+
in the presence of NO
2
–
. In seedlings pretreated with NH
4
+
subsequent induction was inhibited only when NH
4
+
was also present during induction, even though pretreated roots accumulated high levels of NH
4
+
. This indicates that inhibition may be regulated by NH
4
+
concentration in the cytoplasm rather than its total accumulation in roots. L-Methionine sulfoximine did not relieve the inhibition by NH
4
+
, suggesting that inhibition is caused by NH
4
+
itself rather than by its assimilation product(s). Ammonium inhibited subsequent expression of NO
3
–
transport activity similarly in roots grown in 0.1, 1.0, or 10 mM NO
3
–
for 24 h (steady-state phase) or 4 d (decline phase), indicating that it has a direct, rather than general feedback effect. Induction of the NO
3
–
transport system was about twice as sensitive to NH
4
+
as compared to the NO
2
–
transport system. This may relate to higher turnover rates of membraneassociated NO
3
–
-transport proteins.Abbreviations Mes
2(N-morpholino)ethanesulfonic acid
- MSO
L-methionine sulfoximine 相似文献
996.
Mehmood Maryam Khan Muhammad Jadoon Khan Muhammad Jawad Akhtar Nadeem Mughal Fizza Shah Syed Tahir Abbas Hyder Muhammad Zeeshan Farrakh Sumaira Sadiq Irfan 《Molecular biology reports》2022,49(3):2059-2071
Molecular Biology Reports - Sesame is an ancient oilseed crop, known for its high oil content and quality. Its sensitivity to drought at early seedling stage is one of the limiting factors... 相似文献
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